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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS2008

NASA Tech Briefs, February 2008

Topics discussed include: Optical Measurement of Mass Flow of a Two-Phase Fluid; Selectable-Tip Corrosion-Testing Electrochemical Cell; Piezoelectric Bolt Breakers and Bolt Fatigue Testers; Improved Measurement of B(sub 22) of Macromolecules in a Flow Cell; Measurements by a Vector Network Analyzer at 325 to 508 GHz; Using Light to Treat Mucositis and Help Wounds Heal; Increasing Discharge Capacities of Li-(CF)(sub n) Cells; Dot-in-Well Quantum-Dot Infrared Photodetectors; Integrated Microbatteries for Implantable Medical Devices; Oxidation Behavior of Carbon Fiber-Reinforced Composites; GIDEP Batching Tool; Generic Spacecraft Model for Real-Time Simulation; Parallel-Processing Software for Creating Mosaic Images; Software for Verifying Image-Correlation Tie Points; Flexcam Image Capture Viewing and Spot Tracking; Low-Pt-Content Anode Catalyst for Direct Methanol Fuel Cells; Graphite/Cyanate Ester Face Sheets for Adaptive Optics; Atomized BaF2-CaF7 for Better-Flowing Plasma-Spray Feedstock; Nanophase Nickel-Zirconium Alloys for Fuel Cells; Vacuum Packaging of MEMS With Multiple Internal Seal Rings; Compact Two-Dimensional Spectrometer Optics; and Fault-Tolerant Coding for State Machines.

Source record↗
DOE OSTI2016

A three-layer magnetic shielding for the MAIUS-1 mission on a sounding rocket

Bose-Einstein-Condensates (BECs) can be used as a very sensitive tool for experiments on fundamental questions in physics like testing the equivalence principle using matter wave interferometry. Since the sensitivity of these experiments in ground-based environments is limited by the available free fall time, the QUANTUS project started to perform BEC interferometry experiments in micro-gravity. After successful campaigns in the drop tower, the next step is a space-borne experiment. The MAIUS-mission will be an atom-optical experiment that will show the feasibility of experiments with ultra-cold quantum gases in microgravity in a sounding rocket. The experiment will create a BEC of 10{sup 5} {sup 87}Rb-atoms in less than 5 s and will demonstrate application of basic atom interferometer techniques over a flight time of 6 min. The hardware is specifically designed to match the requirements of a sounding rocket mission. Special attention is thereby spent on the appropriate magnetic shielding from varying magnetic fields during the rocket flight, since the experiment procedures are very sensitive to external magnetic fields. A three-layer magnetic shielding provides a high shielding effectiveness factor of at least 1000 for an undisturbed operation of the experiment. The design of this magnetic shielding, the magnetic properties, simulations, and tests of its suitability for a sounding rocket flight are presented in this article.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2014

Quantum-field-theoretical approach to phase–space techniques: Symmetric Wick theorem and multitime Wigner representation

In this work we present the formal background used to develop the methods used in earlier works to extend the truncated Wigner representation of quantum and atom optics in order to address multi-time problems. Analogs of Wick’s theorem for the Weyl ordering are verified. Using the Bose–Hubbard chain as an example, we show how these may be applied to constructing a mapping of the system in question to phase space. Regularisation issues and the reordering problem for the Heisenberg operators are addressed.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2026

Redefining precision interferometry and spectroscopy with high-performance optical interference coatings

High-performance optical interference coatings have transformed precision interferometry and spectroscopy by enabling unparalleled control over light–matter interactions. This review explores recent innovations in ion-beam sputtered amorphous dielectric, as well as substrate-transferred crystalline coatings, and their impact on systems at the forefront of precision metrology. These state-of-the-art coating techniques generate multilayers with ultralow optical losses, yielding mirrors with exceptional reflectivity. Refinements in their noise performance push the ultimate limits of sensitivity, resolution, and stability in demanding laser-based metrology applications. These technologies underpin the most advanced timekeeping and spatial measurement tools, enabling high-finesse reference cavities for the world’s most precise optical atomic clocks and low-noise reflective test masses for km-baseline gravitational-wave detectors. Emerging hybrid designs combining these techniques expand access to the mid-infrared spectral region, enabling the first ultralow-optical-loss coatings in the 3000–5000 nm wavelength range for enhanced spectroscopy and trace-gas detection. We highlight how these technologies redefine coating performance metrics and set new benchmarks in quantum science, fundamental physics, and precision optical sensing.

Cole, Garrett D. [University of Arizona, Tucson, A↗
DOE OSTI2011

Realization of a Distributed Bragg Reflector for Propagating Guided Matter Waves

We report on the experimental study of a Bragg reflector for guided, propagating Bose-Einstein condensates. A one-dimensional attractive optical lattice of finite length created by red-detuned laser beams selectively reflects some velocity components of the incident matter wave packet. We find quantitative agreement between the experimental data and one-dimensional numerical simulations and show that the Gaussian envelope of the optical lattice has a major influence on the properties of the reflector. In particular, it gives rise to multiple reflections of the wave packet between two symmetric locations where Bragg reflection occurs. Our results are a further step towards integrated atom-optics setups for quasi-cw matter waves.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2017

On the possibility of observing chaotic motion of cold atoms in rigid optical lattices

The possibility of experimental observation of chaotic motion of cold atoms in a one-dimensional rigid optical lattice without any modulation of its parameters and additional impact is demonstrated theoretically and numerically. This effect of deterministic chaos arises near the optical resonance due to the nonlinear coupling of electronic and mechanical degrees of freedom in the atom. In a certain range of resonance detunings, at each crossing of the lattice-forming standing wave node by the atom, the atomic dipole moment changes pseudorandomly in a step-like manner, accompanied by an appropriate change in the atom momentum. This leads to the effect of chaotic wandering of atoms, possessing the properties of the classical deterministic chaos, namely, to the exponential sensitivity of atomic trajectories to small variations of the initial conditions and/or the control parameters. With time, part of atoms from the initial cloud changes the direction of their motion to the opposite one, which can be detected in a real experiment. Numerical experiments with lithium atoms with the spontaneous emission taken into account show that by varying the laser radiation intensity (normalised detuning of resonance) in the rigid optical lattice, one can implement the transition from the regular regime of the atomic motion to the chaotic wandering in a real experiment. (paper)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Optical Two-Photon Surface Nonlinear Waves

A theory of the optical surface two-photon small-amplitude breather in a multilayer system of the isotropic and anisotropic left-hand metamaterials, when there are a graphene monolayer (graphene-like twodimensional material) and a transition layer with impurity optical atoms (semiconductor quantum dots), is constructed. It is shown that the system of constitutive equations for two-photon transitions and wave equation for a surface plasmon–polariton TM mode are reduced to the nonlinear Schrödinger equation with damping. Explicit analytical expressions for a surface two-photon small-amplitude self-induced transparency breather (0π-pulse) are obtained. It is shown that the optical conductivity of graphene leads to the exponential damping of intensity of a surface two-photon nonlinear wave during the propagation. One- and two-photon small-amplitude breathers in graphene are compared, and it is shown that differences between their parameters are substantial.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2016

Quantum Yield Heterogeneity among Single Nonblinking Quantum Dots Revealed by Atomic Structure-Quantum Optics Correlation

Physical variations in colloidal nanostructures give rise to heterogeneity in expressed optical behavior. This correlation between nanoscale structure and function demands interrogation of both atomic structure and photophysics at the level of single nanostructures to be fully understood. In this paper, by conducting detailed analyses of fine atomic structure, chemical composition, and time-resolved single-photon photoluminescence data for the same individual nanocrystals, we reveal inhomogeneity in the quantum yields of single nonblinking “giant” CdSe/CdS core/shell quantum dots (g-QDs). We find that each g-QD possesses distinctive single exciton and biexciton quantum yields that result mainly from variations in the degree of charging, rather than from volume or structure inhomogeneity. We further establish that there is a very limited nonemissive “dark” fraction (<2%) among the studied g-QDs and present direct evidence that the g-QD core must lack inorganic passivation for the g-QD to be “dark”. Finally and therefore, in contrast to conventional QDs, ensemble photoluminescence quantum yield is principally defined by charging processes rather than the existence of dark g-QDs.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Topography, complex refractive index, and conductivity of graphene layers measured by correlation of optical interference contrast, atomic force, and back scattered electron microscopy

The optical phase shift by reflection on graphene is measured by interference contrast microscopy. The height profile across graphene layers on 300 nm thick SiO{sub 2} on silicon is derived from the phase profile. The complex refractive index and conductivity of graphene layers on silicon with 2 nm thin SiO{sub 2} are evaluated from a phase profile, while the height profile of the layers is measured by atomic force microscopy. It is observed that the conductivity measured on thin SiO{sub 2} is significantly greater than on thick SiO{sub 2}. Back scattered electron contrast of graphene layers is correlated to the height of graphene layers.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2015

Partial Support of the Committee of Atomic, Molecular, and Optical Sciences (Final Report, September 30, 2008 to June 30, 2014)

This report is the final report for the 2008-2014 cycle of DOE support for the Committee on Atomic, Molecular, and Optical Sciences. Highlights of the committee’s activities over this period included: Meetings of the committee were held semiannually (Washington, DC in April and Irvine, CA in October) for four of the six years and annually the last two years (Washington, DC in April). Committee meetings included half-day focus sessions on each of the areas identified in the last AMO decadal survey as having great scientific promise and short summaries of the focus session were prepared and delivered to sponsoring agencies. CAMOS initiated a study that has been funded on high intensity lasers. DOE support for CAMOS has been of central importance to the committee’s ability to continue to fulfill its mandate to the Board on Physics and Astronomy and to the wider atomic, molecular, and optical sciences research community.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2021

422 Million intrinsic quality factor planar integrated all-waveguide resonator with sub-MHz linewidth

High quality-factor (Q) optical resonators are a key component for ultra-narrow linewidth lasers, frequency stabilization, precision spectroscopy and quantum applications. Integration in a photonic waveguide platform is key to reducing cost, size, power and sensitivity to environmental disturbances. However, to date, the Q of all-waveguide resonators has been relegated to below 260 Million. Here, we report a Si 3 N 4 resonator with 422 Million intrinsic and 3.4 Billion absorption-limited Qs. The resonator has 453 kHz intrinsic, 906 kHz loaded, and 57 kHz absorption-limited linewidths and the corresponding 0.060 dB m -1 loss is the lowest reported to date for waveguides with deposited oxide upper cladding. These results are achieved through a careful reduction of scattering and absorption losses that we simulate, quantify and correlate to measurements. This advancement in waveguide resonator technology paves the way to all-waveguide Billion Q cavities for applications including nonlinear optics, atomic clocks, quantum photonics and high-capacity fiber communications.

36 MATERIALS SCIENCE↗
DOE OSTI2017

A novel artificial condensed matter lattice and a new platform for one-dimensional topological phases

Engineered lattices in condensed matter physics, such as cold-atom optical lattices or photonic crystals, can have properties that are fundamentally different from those of naturally occurring electronic crystals. We report a novel type of artificial quantum matter lattice. Our lattice is a multilayer heterostructure built from alternating thin films of topological and trivial insulators. Each interface within the heterostructure hosts a set of topologically protected interface states, and by making the layers sufficiently thin, we demonstrate for the first time a hybridization of interface states across layers. In this way, our heterostructure forms an emergent atomic chain, where the interfaces act as lattice sites and the interface states act as atomic orbitals, as seen from our measurements by angle-resolved photoemission spectroscopy. By changing the composition of the heterostructure, we can directly control hopping between lattice sites. We realize a topological and a trivial phase in our superlattice band structure. We argue that the superlattice may be characterized in a significant way by a one-dimensional topological invariant, closely related to the invariant of the Su-Schrieffer-Heeger model. Our topological insulator heterostructure demonstrates a novel experimental platform where we can engineer band structures by directly controlling how electrons hop between lattice sites.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Spectroscopy of atoms in an optical dipole trap using spectrally selective heating by a probe laser field

Spectral properties of atoms localised in an optical dipole trap are studied using the method of spectrally selective heating by a probe field. The method is based on measuring the number of atoms in a trap after they interact with a probe field. The dependence of the number of atoms on the frequency of the probe field fully characterises the shift and width of the spectral absorption line of trapped atoms. (paper)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2019

Porous Microcapsule-Based Regenerating Superhydrophobic Coating on 304L SS and Its Corrosion Properties

We report fabrication of a regenerating superhydrophobic coating on 304L stainless steels, with superior corrosion resistance, using porous microcapsules made of calcium hydroxide as a core and a polymeric shell consisting of ethyl cellulose and poly methyl methacrylate. The synthesized microcapsules are characterized using optical, atomic force and scanning electron microscopic techniques, x-ray diffraction, Fourier transform infrared spectroscopy and immersion tests. The diameter of porous and permeable microcapsules ranges from 2 to 20 μm. On immersion of the coated surface in sodium stearate solution, the calcium hydroxide from the core diffuses through the pores of microcapsules and forms nanocrystalline hydrophobic calcium stearate needles pointing outward that repel water molecules. The maximum water contact angle obtained was 155.7° ± 2.05°. The micro-nanoscale roughness of the surface was evident from the AFM measurement. The cross-hatch tape adhesion test confirmed the strong adherence of the superhydrophobic coating. On damage of the superhydrophobic coating, the regeneration is achieved by immersing it in sodium stearate solution for 6 h where a 10° increase in contact angle is observed. Electrochemical studies in 0.1 M NaCl showed significant decrease in the passive current density and a delayed pitting, confirming better corrosion resistance of the coating in chloride environment.

36 MATERIALS SCIENCE↗
DOE OSTI2022

In situ infrared nanospectroscopy of the local processes at the Li/polymer electrolyte interface

Solid-state batteries possess the potential to significantly impact energy storage industries by enabling diverse benefits, such as increased safety and energy density. However, challenges persist with physicochemical properties and processes at electrode/electrolyte interfaces. Thus, there is great need to characterize such interfaces in situ, and unveil scientific understanding that catalyzes engineering solutions. To address this, we conduct multiscale in situ microscopies (optical, atomic force, and infrared near-field) and Fourier transform infrared spectroscopies (near-field nanospectroscopy and attenuated total reflection) of intact and electrochemically operational graphene/solid polymer electrolyte interfaces. We find nanoscale structural and chemical heterogeneities intrinsic to the solid polymer electrolyte initiate a cascade of additional interfacial nanoscale heterogeneities during Li plating and stripping; including Li-ion conductivity, electrolyte decomposition, and interphase formation. Moreover, our methodology to nondestructively characterize buried interfaces and interphases in their native environment with nanoscale resolution is readily adaptable to a number of other electrochemical systems and battery chemistries.

42 ENGINEERING↗
DOE OSTI2021

Search for topological defect dark matter with a global network of optical magnetometers

Ultralight bosons such as axion-like particles are viable candidates for dark matter. They can form stable, macroscopic field configurations in the form of topological defects that could concentrate the dark matter density into many distinct, compact spatial regions that are small compared with the Galaxy but much larger than the Earth. Here we report the results of the search for transient signals from the domain walls of axion-like particles by using the global network of optical magnetometers for exotic (GNOME) physics searches. We search the data, consisting of correlated measurements from optical atomic magnetometers located in laboratories all over the world, for patterns of signals propagating through the network consistent with domain walls. The analysis of these data from a continuous month-long operation of GNOME finds no statistically significant signals, thus placing experimental constraints on such dark matter scenarios.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2014

Neutron irradiation effects on metal-gallium nitride contacts

We have measured the effect of fast and thermal neutrons on GaN Schottky barriers and ohmic contacts using current–voltage and transmission line method electrical techniques, optical, atomic force and scanning electron microscopy morphological techniques, and X-ray photoemission spectroscopy chemical techniques. These studies reveal a 10{sup 15} n/cm{sup 2} neutron threshold for Schottky barrier ideality factor increases, a 10{sup 15} n/cm{sup 2} fast plus thermal neutron threshold for ohmic contact sheet and contact resistance increases, and 10{sup 16} n/cm{sup 2} neutron fluence threshold for major device degradation identified with thermally driven diffusion of Ga and N into the metal contacts and surface phase changes. These results demonstrate the need for protecting metal-GaN contacts in device applications subject to neutron radiation.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

Hole mobility enhancement of MEH-PPV film by heat treatment at T{sub g}

The hole mobility of poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylene vinylene] (MEH-PPV) film was measured using the time-of-flight method. The hole mobility was enhanced 4-fold after annealing at around the glass transition temperature (T{sub g}). Optical, atomic force, and Kelvin force microscopies, and grazing-incidence X-ray diffraction measurements indicate the enhancement can be attributed to a homogeneous film structure, a homogeneous Fermi level energy, and a face-on oriented structure, all of which were established by annealing at T{sub g}.

36 MATERIALS SCIENCE↗